scugpg Posted October 9, 2011 Report Share Posted October 9, 2011 Hey guys I have a 50hp Merc carburated 4 stroke and it seems to run rough at idle sometimes and occasionally stall out. Trolling around 3-5mph it sometimes misses. Running 2000rpm and above it runs great and seems to run better after going WOT for a little while. Changed the fuel filter, plugs, ran a bunch of seafoam through it this year. Runs better after plug change but still happens consistently. I also notice that the fuel bulb doesn't stay stiff on this motor...I've heard that this can be typical on these models but not sure. Has a built in fuel tank and put in a new fuel bulb this year. What else could be causing the issue? I know it was sitting quite a bit last year so hoping there isn't a bunch of water in the tank under the floor. Would be a real pain to pull the floor up. Any ideas? Thanks! Link to comment Share on other sites More sharing options...
bushart Posted October 9, 2011 Report Share Posted October 9, 2011 I've got the same motor You may have the Ethanol blues---a degraded piece of crap in your carbs Took mine to a merc dealer who blew out the ports and reset the carbs--sorry hate to be the bearer of bad news PS I have the tiller so mines better Link to comment Share on other sites More sharing options...
scugpg Posted October 9, 2011 Author Report Share Posted October 9, 2011 I have the tiller too Maybe I'll drain the carbs and add more sea foam. Do you have issues with the fuel bulb on that motor? Link to comment Share on other sites More sharing options...
bushart Posted October 9, 2011 Report Share Posted October 9, 2011 The primer bulb on mine will get stiff---did you get the ethanol free bulb----no kiddin Link to comment Share on other sites More sharing options...
scugpg Posted October 9, 2011 Author Report Share Posted October 9, 2011 It's an attwood ethanol resistant one....the old one did the same thing so thinking it's not the bulb Link to comment Share on other sites More sharing options...
Tybo Posted October 9, 2011 Report Share Posted October 9, 2011 If it's a older engine.Replace all rubber fuel lines will ethanol suitable. Link to comment Share on other sites More sharing options...
Pigeontroller Posted October 10, 2011 Report Share Posted October 10, 2011 Yep, fuel lines or carbs... Link to comment Share on other sites More sharing options...
scugpg Posted October 10, 2011 Author Report Share Posted October 10, 2011 Did some troubleshooting today and it looks like something above the bulb causing it to lose prime. Where the fuel pump is I can hear hissing when I prime. It doesn't leak or seem like it's a gasket so maybe the pump check valve? Link to comment Share on other sites More sharing options...
Garnet Posted October 10, 2011 Report Share Posted October 10, 2011 Dish soap and water. Spray hoses, connections. Look for bubbles. Link to comment Share on other sites More sharing options...
scugpg Posted October 10, 2011 Author Report Share Posted October 10, 2011 Dish soap and water. Spray hoses, connections. Look for bubbles. Good point! I tightened the in/out connections at the fuel pump but could still hear hissing. It honestly sounded like it was from inside the housing but will give that a try its got to be somewhere. FYI on the fuel bulb, it will prime solid but go down a minute or two after priming....whether starting it or not. Link to comment Share on other sites More sharing options...
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